1. Field of the Invention
The present invention relates to an inter-entity coupling method, an inter-entity coupling apparatus, and an inter-entity coupling system for content protection in a broadcast environment.
2. Description of the Related Art
In general, a broadcast service refers to a service scheme in which if a server controlling the broadcast service transmits an encrypted service, then a plurality of terminals can receive the encrypted service.
At present, a greater number of broadcast services are changing from a free-service into a charged service, (e.g., a pay-to-view service). A Digital Rights Management (DRM) technology using a user's Rights Object (RO) has been introduced because of a necessity to provide a copyright protection technology for preventing indiscriminate reproduction and distribution of content (e.g., digital content).
Content provided from a service provider is protected as shown in FIG. 1, which is a diagram illustrating the configuration of a conventional common DRM system. The DRM technology is a typical security technique for protecting content, and to prescribe a right-of-use for encrypted content. Devices and/or systems which use the DRM technology include a terminal 3 which reproduce content using an RO, and a Rights Issuer (RI) which can create and issue the RO defining the rights of use for the content and so forth. This RI belongs to a service provider 5.
The terminal 3 establishes a safe channel through an authentication procedure with the RI, and acquires the RO over the established channel. At this time, since the RO is decrypted by means of the DRM technology, it is possible to prevent the contents from being used without authorization. That is, multimedia information included in the encrypted content cannot be reproduced before the encrypted content is decrypted and executed by means of the DRM technology through such an RO.
Conventional content protection methods perform an authentication procedure between a service provider and only a single terminal. Moreover, a related standard in a mobile communication environment includes the Open Mobile Alliance (OMA) DRM v2.0 technology, which is used by content providers to define how content can be used. However, a concrete standard related to content protection for a plurality of terminals using the broadcast service in the mobile communication environment is not yet proposed.
Furthermore, although several content protection methods in the broadcast environment exist in the 3rd Generation Partnership Project (3GPP), 3GPP2, etc., networks these content protection methods are dependent on networks in which they are used (e.g., the 3GPP network and so forth).
As stated above, conventional content protection methods are based on the existing 3GPP network, and detailed methods regarding how entities participating in a broadcast network operate in order to protect digital content have not yet been proposed.